Long-lived waste storage in deep geological formation: limitation of circulations by permeable hydraulic barriers

The general principle which is at present followed for the concepts of deep storage of long-lived radioactive waste aims to separate the radioelements form the biosphere with isolation barriers, using the multi-barrier concept: waste conditioning, worked barrier and geological barrier. The original approach which is presented thereafter must be considered as complementary to the previous one. It consists in creating a storage concept with a hydraulic draining barrier which would be located in the close field, in order to isolate the actual storage area hydraulically, and so to form a partial hydraulic Faraday cage. A detailed tridimensional model, which was carried out with the help of DEDALE-3D software (hydraulic and transportation calculation), enabled the researchers to analyse the runoff in the close field in a reference site (without any draining barrier), which is particularly characterized by important contrasts in geometry and permeability. The analysis has guided the research for storage concepts which seem to have an increased containment capacity. Then, the tridimensional modeling of these concepts enabled the researchers to prove the relevance of the followed approach. (authors). 5 refs., 11 figs